Push button switch

ABSTRACT

Simple low profile multi-contact push button switch assembly with movable contacts positioned within the push button itself. The push button slides within a tubular housing secured to a bass in which conducting pins are mounted. The push button is spring biased with respect to the base and moves to bring the contacts into engagement with the conducting pins. The movable contacts have relatively long spring arms with ends which move along ribs in the housing and into wiping engagement with fixed contacts formed by the conducting pins. One or more movable contacts can be provided with each push button, and the contacts may be of different shapes and can be interconnected to provide different switching arrangements. The conducting pins extend through the base forming terminals for connection to a circuit, and the base may be mounted directly on a printed circuit board with the terminals soldered to the conductors thereon. To facilitate the layout of the circuit on the board, the conducting pins are staggered, and the ends of the movable contacts are offset to directly engage the pins. A plurality of switches may be provided in an array for various applications, such as to provide numerical, coded keyboards.

United States Patent 1191 Kobernus' 1451 June 1 1974 PUSH BUTTON SWITCH[75] Inventor: William D. Kobernus, La Grange Park, Ill.

[73] Assignee: Grayhill, Inc., La Grange, Ill. [22] Filed: Mar. 12, 1973[2]] Appl. No.: 340,251

[52] U.S. Cl. 200/159 A, 200/16 D [5l] Int. Cl. 1101b 13/64 [58] Fieldof Search 200/159 A, 16 D,-16 C, '200/159 R- [56] References CitedUNITED STATES PATENTS 1,906,085 4/1933 Norviel 200/16 D 3,038,053 6/1962Long et al 200/159 A 3,072,757 1/1963 Gluck 200/16 D 3,l42,742 7/l964Kaleba et al 3,261,955 7/l966 Martin 3,699,292 l0/l972 Ohkita ZOO/l6 DPrimary Examiner-George Harris 1 Attorney, Agent, or FirmMueller,Aichele & Ptak assembly with movable contacts positioned within the pushbutton itself. The push button slides within a tubular housing securedto a bass in which conducting pins are mounted. The push button isspring biased with respect to the base and moves to bring the contactsinto engagement with the conducting pins. The movable contacts haverelatively long spring arms with ends which move along ribs in thehousing and into wiping engagement with fixed contacts formed by theconducting pins. One or more movable contacts can be provided with eachpush button, and the contacts may be of different shapes and can beinterconnected to provide different switching arrangements. Theconducting pins extend through the base forming terminals for connectionto a circuit, and the base may be mounted directly on a printed circuitboard with the terminals soldered to the conductors thereon. Tofacilitate the layout of the circuit on the board, the conducting pinsare staggered, and the ends of the movable contacts are offset todirectly engage the pins, A plurality of switches may be provided in anarray for various applications, such as to provide num'erical,'codedkeyboards.

18 Claims, 13 DrawingFigures 3 38 .r'-. w '1- I 1 25a 1 I l.

r -"T 3e 5 H 118 I 5 L PUSH BUTTON SWITCH BACKGROUND OF THE INVENTIONPush button switches are used in many applications, such as on controlpanels wherein the buttons are operated to cause various controloperations. In some cases, a plurality of switches are required as toprovide a numerical input. In many applications, push buttons arerequired on relatively small apparatus, and when a plurality of switchesare required, the size of the buttons and the switches operated therebymust be small so that the size of equipment is not unduly increasedthereby.

In the past it has been common practice to provide push button switcheswherein'the actuator is coupled to the switch structure, but isphysically separate therefrom. This results in a structure which isrelatively large and is not suitable for use with miniature equipment.In many cases, it has been necessary to custom design the switch intothe equipment to conserve space, thereby resulting in increased cost.Also, known switch structures are not available with the desiredversatility of contact arrangements, and in arrays or modules includinga plurality of switches which can be used to provide the numbers andarrangement of switches required in different applications.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide an improved low profile push button switch structure.

A further object of the invention is to provide a push button switchwherein at least a portion of the switch contact structure is providedwithin the push button itself, so that relatively long spring contactarms are provided in a small overall structure.

Another object of the invention is to provide a small push button switchhaving a base with pins adaptable to be connected to a circuit board,with the pins forming fixed contacts which are selectively engaged bymovable contacts provided within the push button actuator.

Still another object of the invention is to provide a push button switchstructure having a base adapted to be mounted on a circuit board, withconducting pins therein positioned to be connected to conductorsthereon, and with movable contacts extending within the push button andhaving resilient ends projecting therefrom for engaging the pins andproviding wiping contact therewith in response to movement of the pushbutton.

A still further object of the invention is to provide a push buttonswitch which may have a plurality of switching contacts provided insmall space, and wherein a plurality of the switches can be combined ina compact switch array.

In practicing the invention, a push button switch assembly is providedhaving a base which is suitable for mounting in various ways, such as ona circuit board. Conducting pins extend through the base having terminalportions for connection to conductors on a circuit board, with the pinsextending above the base to form fixed switch contacts. A tubularhousing is secured to the base within which a push button is moveablypositioned. The push button is open on the side facing the base and hasgrooves therein for receiving U-shaped movable contacts. The contactshave spring arms with grooves in the housing, with a'coil spring beingpositioned between the base and the insert to hold the push button inthe upper or unactuated position. The push button may have a cover withan edge adapted to engage a shoulder in the housing to prevent removalof the push button from the housing. By use of a transparent cover,indicia can be provided on the push button which is apparent through thecover, or indicia can be placed on or within the cover itself.

To facilitate connection of the pin terminals to conductors on a circuitboard in a particular pattern, the position of the pins is staggered.The ends of the movable contacts are offset so that the contact endscorrectly engage the pins. .A single contact can be provided in eachpush button or a plurality of contacts can be used, and the contacts canbe inter-connected as desired. The ends of the contacts can be ofdifferent lengths so that connection is established with the conductingpins at different points in the movement of the push button. Thispermits the closing of some of the switch contacts prior to the closingof other contacts.

The base and housing are sealed together to provide an elclosure aboutthe contacts to hold out foreign material. A single base and housing canbe used for a plurality of push button switches which are provided as amodule. In such case, the construction of the push buttons and thecontacts can be the same as for individual switches.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of the pushbutton switch of the invention;

FIG. 2 is a side view of the push button switch;

FIG. 3 is a cross-sectional view of the switch showing the internalconstruction;

FIG. 4 is a bottom view of the switch showing the terminal arrangement;

FIG. 5 is a cross-sectional view of the switch along the lines 5-5 ofFIG. 3;

FIG. 6 is a cross-sectional view along the lines 6-6 of FIG. 3;

FIGS. 7 and 8 are detailed views of the U-shaped movable switch contact;

FIG. 9 shows the switch with the movable switch contact in engagementwith the contact pins;

FIG. 10 shows an alternate movable contact construction;

FIG. 11 illustrates a common movable contact for connecting more thantwo terminals;

FIG. 12 is a top view of a module including six push button switches;and

FIG. 13 shows the base of the switch module of FIG. 12.

DETAILED DESCRIPTION FIG. 1 is a top view of the switch of the inventionshowing the push button 10, which is of rectangular (square)configuration, within the tubular housing 12. The push button canobviously be of a different shape, such as round. FIG. 2 is a side viewwhich in addition to showing the push button .10 and the housing 12,shows the base member 14 and the terminals 16 extending therefrom. Thehousing 12 has an upper reduced section 13 from which the push button exnoted that the terminals 16 are molded in the base 14,

and are the bottom ends of conducting pins which have portions 18extending above the base forming fixed switch contacts. Terminals andfixed contacts can be provided which are of other constructions. Thepush button 10, is formed by a five sided cubical member 20, which hasan open side facing the base 14, and a cover 22positioned about themember andhaving an outwardly extending edges 23 which holds the pushbutton assembled to .the housing 12. The edge 23 engages internalshoudler 24, on the housing to limit the upward movement of the pushbutton. The push button can be provided as a'single molded member withthe edge 23 thereon, and can be provided by two-shot molding with afirst part having indicia molded thereon, and the secondmolding-surounding the indicia.

One or more U-shaped spring contact members 25 are provided, with thebight thereof extending within the hollow push button 10. Ribs 21 extendinwardly from opposite walls of the member 20 providing grooves withinwhich the arms of the spring contacts 25 are positioned, with aplurality of grooves being provided to receive a plurality of movablespring contacts. In the construction shown, up to four movable contactscan be used, but the switch can be constructed to receive a larger-orsmaller number of movable contacts. An insert 28 is positioned withinthe member 20 in engagement with the contacts 25 at the center thereof.

This member has an 1 opening 30 for receiving coil spring 32 which holdsthe push button 10 in its upward position. The spring 32 can bepositioned about a central projection 33 on the base 14 so that it isretained in its proper position. 1

FIGS. 5 and 6, which are cross-sectional views along the lines 5-5 and6-6 of FIG. 3,-further illustrate the construction of the switch. FIG. 5showsthe bottom of the insert 28, and shows the extensions 29-thereonwhich extends into slots 31 in the sidesof the housing 12. This guidesthe insert 28 as itmoves with the push button 10 in the tubular housing12. FIG. 5 also shows the ribs 21 along the sides of the member 20 whichform the grooves for receiving the contacts 25. FIGS. 5 and 6 show theuse of only a single movable contact 25, but it will be apparent thatthree other movable contacts can also be used in the four slots providedin the construction illustrated. l

I Thehousing 12 is positioned on. the base 14 as best shown in FIGS. 3and 6. The housing 12 has an edge 35 which fits within the upturned edge36 of the base 14. Projections 40 extend from the housing into openings42 in the base to key these'two parts in the proper positions. Aprojection 44 may beprovided adjacent the edge of the base 14, to extendinto a recess 46 in one side of the housing 12, to prevent incorrectassembly of the base and the housing. The housing and base can be madeof plastic material and secured together by ultrasonic welding, or otherknown means, to seal the enclosure about the contacts'This preventsentry of contaminants which may be present, as when the base isconnected to a circuit board by machine soldering. By use of thisconstruction the base 14 can be molded of thermosetting material and thehousing 12 molded of thermoplastic material. As the base is adapted tobe positioned on a-circuit board and have the terminals positioned inopenings therein and soldered to conductors thereon, it will besubjected to the high temperatures used in automatic soldering, so itmust be constructed to material which will withstand these temperatures.The housing can be constructed of less expensive thermoplastic materialwhich can be'secured to the base by ultrasonic welding, and can beprovided in different button 10 is pressed down, the movable'contact 25will move downwardly, so that the curved ends 26 thereof will engage thecylindrical fixed contacts 18 formed by the contact pins, and wipetherealong, as shown in FIG.

9. As the fixed contacts 18 are cylindrical, and the ends 26 of movablecontacts 25 are curved, the engagement between the fixed and movablecontacts will be at a point, and the wiping action of the movablecontact 25 along the fixed contact 18 would be along a line. This willact to interconnect the terminals 16 to complete a circuit therethrough,thus providing the normal switch action. If desired, the fixed contacts18 can be positioned so .that engagement thereof by the movable springcontact results in a detent action which can be felt by the personoperating the push button. When the push button 10 is released, the coilspring 32 will move the button upwardly so that the movable contact 25moves to a position wherein the ends 26 thereof are above and out ofengagement with the contacts 18. This will open the circuit through theterminals 16. Although a normally open switch contact arrangement isillustrated, a normally closed contact arrangement can' be provided.

It is apparent from FIG. 3 thatthe U-shapedmovable switch contact 25 isin contact with the member 20 and the insert 28 only at the-centerthereof. This engagement'is provided by projection 48 on the member 20and by projection 49 on the insert 28. This allows the full lengths ofthe arms of contact member 25 to move resiliently for good springcontact action. The contact 25 is constructed from conducting springmaterial, such as beryllium copper to provide effective switch actionfor a large number of operations. The ends curved 26 of the springcontact member 25 engage a pair of ribs 38 on the housing 12 when thebutton '10 is in the unactauted position. The ribs have rounded surfacespositioned to engage the contact ends 26 on opposite sides of the centerpart thereof which engages the contact 18. The center of the contact endwhich provides the switching action, therefore, does not make and breakon the plastic ribs to pick up contaminants which would interfere withthe switching action (FIG. 5). v

FIG. 4 is a bottom view of the base 14 showing the placement of theterminals 16. Terminals need be provided only at the positions where thecontact portions will be engaged by movable contacts. It will be notedthat the terminals are staggered, and this positioning is desirable whenthe switch is used in a circuit board. This allows freedom in the designof the conductor pattern, and facilitates connection of the terminals 16to the conductors on the circuit board.

FIG. 7 and 8 are detail views of the switch contact 25 and illustratethat the ends 26 thereof are offset with respect to the bight or bodyportion of the contact so that they will engage the pin contacts 18 whenposi tioned as shown in FIG. 4. FIGS. 5 and 6 also show the offset endsof the contacts. As previously stated, the ends 26 of the movablecontacts as they move upward engage ribs 38 on the housing 12, with theribs being positioned to engage the contact ends on opposite sides ofthe parts thereof which engage the fixed contact pins 18.

FIG. shows an unsymmetrical contact with can be used'in the switch,whereas the contact shown in FIG. 7 is symmetrical. The end 260 of thecontact 25 is longer than the end 26b. This causes the end 26a to engagea contact pin 18 during movement of the push button, prior to engagementof a contact pin by the end 2612. This may be used to make a particularconnection at a later point in the movement of the push button 10 thananother connection is made by such movement.

FIG. 11 shows an embodiment wherein a plurality of U-shaped contacts areprovided by a single conducting member 50. This member is U-shaped andcan be of the shape shown in FIG. 7. The single conducting member 50 hasends 51 and 52 which connect oppositely positioned conducting pins 18,ends 53 and 54 which connect another pair of oppositely positioned pins,and ends 55 and 56 which connect a third pair of oppositely positionedpins 18. Since this is a common conducting member, all of the pinsengaged by the ends of the contact 50 will be connected together. One ormore of the ends can be short, as shown by end 26b in FIG. 10, ifdesired.

FIG. 12 is a top viewof a switch array or module which includes six pushbutton switches of the invention. A common housing 60 is provided havingsix tubular recesses for receiving the six push buttons marked A, B, C,D, E and F. FIG. 13 is a view of the base member 62 for receiving thehousing 60, and shows the conducting pins 18 which form the fixedcontacts engaged by the movable contacts carried by the push buttons.Openings 64 are provided in the base 62 for receiving pins 65 in thehousing 60 to correctly position the housing with respect to the base.The con struction of the push buttons 10, and the contacts 25 andinserts 28 therein, can be exactly the same as illustrated in FlGs. 1 to8. The tubular portions of the housing can also have the sameconfiguration as in the single switch housing illustrated in FIGS. 1 to6.

The push button switch of the invention has been found to be highlysatisfactory in commercial applications. The switch has a low profile,but because of the positions of the movable contacts within the pushbuttons, and the support thereof only at the center, the contact armsare relatively long and the curved contact ends thereof provide wipingaction along a line on the cylindrical fixed contacts for highlyeffective switch contact action. The use of a separate housing and basefacilitates the molding of the parts, and the sealing of the partstogether prevents the entry of foreign material into the space about thecontacts. The push buttons can be provided in two parts with atransparent cover for protecting the indicia or as a single part, whichmay be formed by two-shot molding. This construction facilitates themolding of the housing and the push buttons of material of variouscolors for the desired appearance.

The push button switch of the invention has been constructed with eachside of the base having a dimension of approximately 0.68 inch, and withthe overall height of the base, housing, and push button in its normalupper position being approximately 0.75 inch.

Switches can be provided individually or in arrays including a pluralityof switches, thereby facilitating the use in different applications. Forexample, switches can be arranged to provide numerical or alphabeticalcoded keyboards. The switch array as illustrated in FIG. 12, whichincludes six switches, has been constructed with a base having adimension of approxispring means coupled to said push button and to saidbase for holding said push button in a normal unoperated position, and

conducting contact means having a portion within said push button andhaving curved contact ends extending therefrom, said contact means beingmovable by said push button to a position wherein said curved endsengage said cylindrical fixed contacts.

2. A switch according to claim 1 wherein said contact means includes aU-shaped movable contact having first and second resilient arms, andwherein each of said arms has a curved end positioned for wipingengagement with one of said cylindrical fixed contacts, which wipingengagement is substantially along a line.

3. A switch according to claim 2 wherein said housing has ribspositioned to be engaged by said ends of said movable contact when saidpush button is in said normal unoperated position, with said ends movinginto positions in engagement with said fixed contacts in response tomovement of said push button.

4. A switch according to claim 2 wherein said housing has a pair of ribspositioned to engage each end of said movable contact, with said ribsengaging said end on opposite sides of the part thereof engaged by saidfixed contact, and wherein said push button is operable to move saidmovable contact so that each of said ends slides along said ribs andthen wipes along said fixed contact.

5. A switch according to claim 1 wherein said hollow push button has aplurality of grooves formed therein, and including a plurality ofU-shaped contacts positioned in said grooves and movable by said pushbutton to positions to engage said fixed contacts.

6. A switch according to claim 5 wherein at least two of said U-shapedcontacts are electrically interconnected.

7. A switch according to claim 5 wherein at least one of said U-shapedcontacts has an end thereof constructed to contact a fixed contact inresponse to movement of the push button at a point in such movementprior to the engagement of a conducting pin by another one of saidcontact ends.

8. A switch according to claim 1 further including an insert memberwithin said push button in engagement with said contact, and whereinsaid spring means enthereof, and said housing has a shoulder engaged bysaid edge when said push button is in said normal unoperated position.

11. A switch according to claim 1 wherein said hollow push buttonincludes an inner portion and a cover portion, and including a movablecontact positioned in said inner portion and movable by said push buttonto a position in engagement with said fixed contacts.

12. A switch according to claim 11 wherein said cover portion is made oftransparent material, and said inner portion includes indicia thereonwhich appears through said cover portion.

13. A switch according to claim 1 including a plurality of cylindricalconducting pins molded into said base and extending-therethrough, saidpins having portions on one side of said base forming said fixedcontacts and terminal portions on the opposite side of said base.

14. A switch according to claim 13 wherein said pins are positioned in astaggered arrangement to facilitate the connection of sadi terminalportions to conductors on a circuit board.

IS. The switch according to claim 14 wherein said contact means includesa U-shaped contact having offset ends for engaging said contact portionsof said 'conducting pins.

16. A switch according to claim 13 wherein said contact means includes aU-shaped contact having first and second resilient arms andwherein eachof said arms has a curved end movable by said push button into wipingengagement with said cylindrical fixed contact portion of one of saidconducting pins.

17. A push button switch array including in combination:

a base having a plurality of cylindrical conducting fixed contact pinsarranged in groups extending therethrough; I

a housing secured to said base having a plurality of tubular portions,each associated with one group of conducting pins;

a hollow push button slidably positoned in each of said tubular housingportions and having anopen side facing said base,

spring means coupled to each of said push buttons and said base forholding said push buttons in normal unoperated positions; and

conducting contact means positioned in each of said push buttons andhaving curved contact ends ex-- tending therefrom, said contact meansbeing movable by said push button to a position wherein said a curvedends engage said cylindrical contact pins of the group associated withthe tubular housing portion in which such push button is positioned.

18. A switch array according to claim 17 wherein said contact meansincludes a U-shaped contact having a center portion and first and secondresilient arms, and wherein each of said arms has a curved endpositioned for wiping engagement with one of said cylindrical contactpins to interconnect the same in response to actuation of said pushbutton.

1. A push button switch including in combination, an insulating basehaving a plurality of cylindrical conducting fixed contacts extendingtherefrom, a tubular housing secured to said base, a hollow push buttonslidably positioned within said housing and having an open side facingsaid base, spring means coupled to said push button and to said base forholding said push button in a normal unoperated position, and conductingcontact means having a portion within said push button and having curvedcontact ends extending therefrom, said contact means being movable bysaid push button to a position wherein said curved ends engage saidcylindrical fixed contacts.
 2. A switch according to claim 1 whereinsaid contact means includes a U-shaped movable contact having first andsecond resilient arms, and wherein each of said arms has a curved endpositioned for wiping engagement witH one of said cylindrical fixedcontacts, which wiping engagement is substantially along a line.
 3. Aswitch according to claim 2 wherein said housing has ribs positioned tobe engaged by said ends of said movable contact when said push button isin said normal unoperated position, with said ends moving into positionsin engagement with said fixed contacts in response to movement of saidpush button.
 4. A switch according to claim 2 wherein said housing has apair of ribs positioned to engage each end of said movable contact, withsaid ribs engaging said end on opposite sides of the part thereofengaged by said fixed contact, and wherein said push button is operableto move said movable contact so that each of said ends slides along saidribs and then wipes along said fixed contact.
 5. A switch according toclaim 1 wherein said hollow push button has a plurality of groovesformed therein, and including a plurality of U-shaped contactspositioned in said grooves and movable by said push button to positionsto engage said fixed contacts.
 6. A switch according to claim 5 whereinat least two of said U-shaped contacts are electrically interconnected.7. A switch according to claim 5 wherein at least one of said U-shapedcontacts has an end thereof constructed to contact a fixed contact inresponse to movement of the push button at a point in such movementprior to the engagement of a conducting pin by another one of saidcontact ends.
 8. A switch according to claim 1 further including aninsert member within said push button in engagement with said contact,and wherein said spring means engages said insert member for holdingsaid push button in said unoperating position.
 9. A switch according toclaim 8 wherein, said contact is U-shaped and has a pair of resilientarms, said push button has a projection engaging said contact onlyadjacent the center thereof, and said insert has a projection engagingsaid contact only adjacent the center thereof, whereby said resilientarms are unrestrained by said push button.
 10. A switch according toclaim 1 wherein said push button has a projecting edge adjacent the openside thereof, and said housing has a shoulder engaged by said edge whensaid push button is in said normal unoperated position.
 11. A switchaccording to claim 1 wherein said hollow push button includes an innerportion and a cover portion, and including a movable contact positionedin said inner portion and movable by said push button to a position inengagement with said fixed contacts.
 12. A switch according to claim 11wherein said cover portion is made of transparent material, and saidinner portion includes indicia thereon which appears through said coverportion.
 13. A switch according to claim 1 including a plurality ofcylindrical conducting pins molded into said base and extendingtherethrough, said pins having portions on one side of said base formingsaid fixed contacts and terminal portions on the opposite side of saidbase.
 14. A switch according to claim 13 wherein said pins arepositioned in a staggered arrangement to facilitate the connection ofsadi terminal portions to conductors on a circuit board.
 15. The switchaccording to claim 14 wherein said contact means includes a U-shapedcontact having offset ends for engaging said contact portions of saidconducting pins.
 16. A switch according to claim 13 wherein said contactmeans includes a U-shaped contact having first and second resilient armsand wherein each of said arms has a curved end movable by said pushbutton into wiping engagement with said cylindrical fixed contactportion of one of said conducting pins.
 17. A push button switch arrayincluding in combination: a base having a plurality of cylindricalconducting fixed contact pins arranged in groups extending therethrough;a housing secured to said base having a plurality of tubular portions,each associated with one group of conducting pins; a hollow push buttonslidablY positoned in each of said tubular housing portions and havingan open side facing said base; spring means coupled to each of said pushbuttons and said base for holding said push buttons in normal unoperatedpositions; and conducting contact means positioned in each of said pushbuttons and having curved contact ends extending therefrom, said contactmeans being movable by said push button to a position wherein saidcurved ends engage said cylindrical contact pins of the group associatedwith the tubular housing portion in which such push button ispositioned.
 18. A switch array according to claim 17 wherein saidcontact means includes a U-shaped contact having a center portion andfirst and second resilient arms, and wherein each of said arms has acurved end positioned for wiping engagement with one of said cylindricalcontact pins to interconnect the same in response to actuation of saidpush button.